In a future America of retreating frontiers and fragmented authority, a small population of ""leos""--legacy of a long ago genetic experiment--combine the mental and physical natures of man and lion. They fit no civilized expectations, but a few men see wholeness and beauty in their bare, nomadic, candidly predatory existence. The leo hero, Painter, is economically and convincingly imagined. Painter's relationship with a human mistress, a subsidiary plot involving falconry, and the criticism of easy ecological faith, are among the more impressive achievements of a spotty but genuinely original book. Crowley may well become one of our more important sf writers.